Hybrid contact lens system and method

ABSTRACT

Methods of manufacturing hybrid contact lenses using a mold are provided. The methods include pouring liquefied resin of a substantially rigid material within an inner section, curing the substantially rigid material, pouring liquefied resin of a substantially flexible material within an outer section and curing the substantially flexible material. In some embodiments, a wall disposed between the rigid and flexible materials is angled and/or bent to increase bonding strength between the rigid and flexible sections. The curing steps involve the application of heat, UV light, or a combination of both heat and UV light.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation-in-part of U.S. patent applicationSer. No. 10/657,061, filed Sep. 5, 2003, which claims priority to U.S.Provisional Application Ser. No. 60/408,618, filed Sep. 6, 2002, thecontents of which are incorporated herein by reference in theirentirety.

FIELD OF THE INVENTION

The present invention generally relates to contact lenses, and moreparticularly to hybrid hard-soft contact lenses.

BACKGROUND OF THE INVENTION

Vision correction is on the verge of a revolution. New technologies tomeasure the aberrations or distortions in the optics of the eye willsoon be available to the public. These new wavefront measurementtechniques such as Shack-Hartmann wavefront sensing or TalbotInterferometry can precisely measure the eye's aberrations so thatvision may be corrected up to 20/10. Wavefront sensing is the method forrapidly, and very accurately, assessing the aberrations in anindividual's eye to create a customized prescription for correction.

However, once the eye's aberrations have been measured, either byconventional methods or by wavefront sensing, these measurements mustthen be transferred into a vision correction system, such as eyesurgery, spectacles, or contact lenses. Recent advances in laserrefractive surgery techniques such as LASIK and photorefractivekeratectomy, as well as improvements in spectacle lens manufacturing nowenable the creation of highly accurate corrective prescriptions forindividuals.

However, this is not the case with contact lenses. Popular soft contactlenses cannot achieve the same result as spectacles or laser refractivesurgery because of dimensional variations in fabrication. Hard contactlenses, which may provide the platform to achieve the results ofspectacles, are not as comfortable as soft contacts and lack thenecessary positional stability on the eye.

Therefore, there exists a need for a hybrid hard-soft contact lens thatcan provide a platform for a corrective prescription and also providethe comfort of soft contact lenses.

One drawback associate with hybrid hard-soft contact lens concerns alack of sufficient bonding between hard and soft sections. This lack ofbonding strength may result in debonding of the soft and hard sectionsat the bonding junctions after short periods of use.

Therefore, there exists a need for methods of manufacturing a hybridhard-soft contact lens that produces sufficient bonding between hard andsoft sections to prevent tearing of the lens at the bonding junctions.

SUMMARY OF THE INVENTION

A hybrid hard-soft contact lens is provided. Several embodiments of theinvention include methods of coupling the hard section of the lens tothe soft section of the lens. Other embodiments of the invention includecontact lens materials that increase oxygen transmission though thelens. Yet other embodiments of the invention are directed tocost-effective manufacturing methods of a hybrid hard-soft contact lens.

The present invention also provides methods of using base curve moldingto produce hybrid hard-soft contact lens that includes sufficientbonding between hard and soft sections to prevent tearing of the lens atthe bonding junctions. Some embodiments include methods of coupling thehard section of the lens to the soft section of the lens, while otherembodiments include cost-effective manufacturing methods of a hybridhard-soft contact lens.

Further embodiments concern the manufacturing of a two-material buttonstarting from a casting. Other embodiments concern the manufacturing ofa two-material button using a preform base curve molding.Advantageously, the preform base curve molding obviates an expensivebase curve lathing operation and only requires front surface lathing tomanufacturing a stock or custom hybrid lens.

One aspect of the present invention involves a method of manufacturing ahybrid contact lens using a mold including an inner section and an outersection that are separated by an inner wall. The method includes thesteps of pouring liquefied resin of a substantially rigid materialwithin the inner section, curing the substantially rigid material,pouring liquefied resin of a substantially flexible material within theouter section and curing the substantially flexible material. The innerwall may be angled and/or bent to increase bonding strength between therigid and flexible sections. The curing steps involve the application ofheat, UV light, or a combination of both heat and ultraviolet (UV)light. A UV blocking material such as4-methacryloxy-2-hydroxybenzophenone can also be incorporated in theformulation to absorb the UV light and to prevent cataract development.

In a preferred embodiment, the inner wall comprises a pre-form opticalgrade divider that divides the substantially rigid material and thesubstantially flexible material. In additional, the inner wallpreferably is bondable with the substantially rigid material and thesubstantially flexible material. According to some embodiments, themethod further includes the steps of coating the inner wall with a UVcurable adhesive to promote bonding with the substantially rigidmaterial and the substantially flexible material and removing the outerwall after the step of curing the substantially flexible material.

Another aspect of the present invention involves a method ofmanufacturing a hybrid contact lens using a block mold having a centralvoid. The method includes the steps of pouring liquefied resin of asubstantially rigid material within the central void, curing thesubstantially rigid material, removing the substantially rigid materialfrom the block mold, attaching a guard to the substantially rigidmaterial, pouring a predetermined amount of liquefied resin of flexiblematerial into an area between the substantially rigid section and theguard and curing the substantially flexible material. The central voiddefines an inner wall that forms the shape of the junction between thesubstantially rigid material and the substantially material. This wallmay be angled and/or bent to increase bonding strength between the rigidand flexible sections. The curing steps involve the application of heat,UV light, or a combination of both heat and UV light. The central voidcan also be molded using less expensive materials for the non-opticalareas.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a front view of a manufacturing step used to construct ahybrid hard-soft contact lens of the present invention;

FIG. 2 is a front view of a contact lens blank after the manufacturingstep illustrated in FIG. 1;

FIG. 3 is a front view of another manufacturing step used to construct ahybrid hard-soft contact lens of the present invention;

FIG. 4 illustrates another manufacturing step used to construct a hybridhard-soft contact lens of the present invention;

FIG. 5 illustrates an alternative manufacturing method of constructing ahybrid hard-soft contact lens of the present invention;

FIG. 6 illustrates several embodiments of interface geometries between ahard section and soft section of a hybrid hard-soft contact lensconstructed according to the present invention;

FIG. 6A illustrates a preferred embodiment of an interface geometrybetween a hard section and soft section of a hybrid hard-soft contactlens constructed according to the present invention;

FIG. 7 is an illustration of a contact lens, several eye components andvisible light rays exiting the eye-contact lens system;

FIG. 8 is another illustration of a contact lens, eye components andvisible light rays, showing the tendency for different colored lightrays to exit the eye at different angles;

FIG. 9 illustrates a hypothetical uniform eye response to the visiblelight spectrum;

FIG. 10 illustrates a photopic eye response to the visible lightspectrum; and

FIG. 11 illustrates one idealized net wavelength response for a contactlens constructed according to the present invention.

FIG. 12 is a cross-sectional view of a hybrid contact lens moldaccording to the principles of the present invention;

FIGS. 13A–13D are cross-sectional views of the hybrid contact lens moldsof FIG. 12, wherein each view includes an alternative inner wall;

FIG. 14 is a cross-sectional view of the hybrid contact lens mold ofFIG. 12 after the inner section has been filled with a substantiallyrigid polymer and cured;

FIG. 15 is a cross-sectional view of the hybrid contact lens mold ofFIG. 14 after the outer section has been filled with a substantiallyflexible polymer and cured;

FIG. 16 is a cross-sectional view of an alternative hybrid contact lensmold according to the principles of the present invention;

FIGS. 17A–17D are cross-sectional views of the hybrid contact lens moldsof FIG. 16, wherein each view includes an alternative junction shape;

FIG. 18 is a cross-sectional view of the hybrid contact lens mold ofFIG. 16 after the central void is filled with a substantially rigidpolymer and cured;

FIG. 19 is a cross-sectional view of the hybrid contact lens mold ofFIG. 18 after separation of the mold;

FIG. 20 is a cross-sectional view of the hybrid contact lens mold ofFIG. 19 after the addition of a guard;

FIG. 21 is a cross-sectional view of the hybrid contact lens mold ofFIG. 20 after the substantially flexible polymer is poured and cured;

FIG. 22 is a cross-sectional view of a further alternative hybridcontact lens mold according to the principles of the present invention;

FIG. 23 is a cross-sectional view of the hybrid contact lens mold ofFIG. 22 after the inner section has been filled with a substantiallyrigid polymer and cured;

FIG. 24 is a cross-sectional view of the hybrid contact lens mold ofFIG. 23 after the outer has been filled with a substantially flexiblepolymer and cured;

FIG. 25 is a cross-sectional view of another alternative hybrid contactlens mold according to the principles of the present invention;

FIG. 26 is a cross-sectional view of the hybrid contact lens mold ofFIG. 25 after the central void has been filled with a substantiallyrigid polymer and cured;

FIG. 27 is a cross-sectional view of the hybrid contact lens mold ofFIG. 26 after separation of the mold;

FIG. 28 is a cross-sectional view of the hybrid contact lens mold ofFIG. 27 after the addition of a guard;

FIG. 29 is a cross-sectional view of the hybrid contact lens mold ofFIG. 28 after the substantially flexible polymer is poured and cured;

FIG. 30 is a cross-sectional view of a pre-formed substantially rigidcenter portion suitable for use with the pre-shape mold of FIGS. 31–33;

FIG. 31 is a cross-sectional view of yet another alternative hybridcontact lens mold according to the principles of the present invention;

FIG. 32 is a cross-sectional view of the hybrid contact lens mold ofFIG. 31 after the outer portion of the bowl-shaped void has been filledwith a substantially flexible polymer and cured; and

FIG. 33 is a cross-sectional view of the hybrid contact lens mold ofFIG. 32 after separation of the mold.

It will be recognized that some or all of the Figures are schematicrepresentations for purposes of illustration and do not necessarilydepict the actual relative sizes or locations of the elements shown.

DETAILED DESCRIPTION OF THE INVENTION

In the following paragraphs, the present invention will be described indetail by way of example with reference to the attached drawings.Throughout this description, the preferred embodiment and examples shownshould be considered as exemplars, rather than as limitations on thepresent invention. As used herein, the “present invention” refers to anyone of the embodiments of the invention described herein, and anyequivalents. Furthermore, reference to various feature(s) of the“present invention” throughout this document does not mean that allclaimed embodiments or methods must include the referenced feature(s).

The present invention is based on a hybrid contact lens platform thatoffers the benefits, without the disadvantages, of both soft and gaspermeable contact lenses—comfort, health, stability, superior optics anddurability. The features of the present invention include lenschemistry, manufacturing processes, optical design and prescribing andfitting processes. One feature of the manufacturing processes andoptical design elements is the ability to make quarter wavelengthcustomization in order to correct for the higher order refractiveaberrations that limit one's ability to see better than 20/20.

Unless defined otherwise, all technical and scientific terms used hereinhave the same meaning as is commonly understood by one of skill in theart to which this invention belongs. In event the definition herein isnot consistent with definitions elsewhere, the definitions set forthherein will control. As used herein, “hybrid” refers to a type ofcontact lens that includes both hard and soft lens elements.

One embodiment of the present invention will correct normal ametropicerrors (myopia, hyperopia and astigmatism) to a higher degree of visualperformance than conventional contact lenses. Another embodiment of thepresent invention will correct for the wavefront-guided higher orderaberrations and will create a new contact lens category, providing“super vision” for those whose visual requirements demand better than20/20 acuity. Yet another embodiment of the present invention willcorrect for presbyopia, the gradually increasing inability to focus atclose distances that usually begins after age 40. Other embodiments ofthe present invention may include contact lenses that incorporateseveral, or all of the above-described features.

Another embodiment of the present invention is a hybrid lens thatcombines the optical clarity, stability and durability of a gaspermeable lens with the comfort of a soft contact lens. This hybrid lenshas a hard gas permeable center chemically bonded to a soft outer skirt.The center is highly oxygen permeable, which is important to maintainingcorneal health. One of the manufacturing processes of the presentinvention enables this gas permeable center to be lathed to quarterwavelength precision, allowing corrections of wavefront-guided higherorder refractive aberrations and providing visual performance betterthan 20/20.

Yet another embodiment hybrid contact lens of the present invention hasa soft outer skirt with a radius of curvature greater than the basecurve of the oxygen permeable center, which is suspended on the softskirt, thus creating a lighter touch above the corneal apex. One featureof this embodiment is that the eyelid force of normal blinking creates aperistaltic-like pump that exchanges the tears under the lens,contributing to overall comfort, and eliminating dryness, the mostfrequent complaint of contact lens wearers. Another feature of thisembodiment is that the tear layer under the lens is not only importantfor comfort and health, but it has optical correction qualities as well.A layer of tears retained behind the base curve of the gas permeablelens of the present invention may correct corneal astigmatism by up toabout ten diopters. Thus, a hybrid contact lens constructed according tothe present invention creates a superior astigmatism correctingcapability that does not rely on orientation and positioning, as do softcontact lenses.

Another embodiment of the present invention comprises a hybrid lens witha substantially rigid center that is chemically bonded to a softer outerskirt. One embodiment of the outer skirt is comprised of a modifiedpoly(2-hydroxyethyl methacrylate) HEMA(poly-2-hydroxyethyl-methacrylate) material. The center is asubstantially rigid gas permeable-type with a gas permeability DK valuegreater than 30. A preferred embodiment center would have a gaspermeability DK value of about 150. However, other embodiments may havea gas permeability DK value that may range between about 30 to about250. In a preferred embodiment of the present invention, thesubstantially rigid center is made from any of the following materials:fluoro-siloxane acrylate, siloxane acrylate, or poly-stryene siloxaneacrylate.

The substantially rigid center section may have a thickness that mayrange between about 0.03 millimeters (mm) to about 0.5 mm., and adiameter that may range between about 4.0 mm. to about 12.0 mm. Theoverall diameter of a hybrid contact lens constructed according to thepresent invention may range between about 10.0 mm. to about 18.0 mm.

The substantially rigid center may have a spherical or ellipsoidalocular (i.e., eye-facing) surface. Unlike soft lenses, the substantiallyrigid center of the present invention contact lens is resistant toprotein deposition. One feature of the present invention contact lens isthat it is also highly resistant to foreign body migration as well asdislodgement from the eye during contact sports, or other vigorousactivities. A contact lens constructed according to the presentinvention also provides excellent centering and vision correction forirregular corneas created by trauma or surgery.

Hybrid Contact Lens Geometry

One embodiment of the present invention comprises a centralsubstantially rigid gas permeable portion having a posterior surfacethat is either spherical, aspherical or toroidal, which is chosen toapproximate the overall toricity and sagittal depth of the cornea to befitted. The rigid gas permeable portion may be optically clear with onlythe reduction in light transmission normally found in similarpolymerized materials. In one embodiment the rigid portion containscolorants and additives that narrow the band of light transmitted by thelens to reduce the chromatic aberration of the lens-eye system. Theanterior or posterior surface of the rigid portion may also have surfacemodification to correct the total low and high order aberrations of thelens-eye system. Further, the surface profile of the anterior orposterior surface may be modified to register the low and high orderaberrations over the optical system of the eye to account for theconsistent natural displacement of the contact lens when applied to theeye. In addition, the surface profile of the anterior or posteriorsurface may be modified to contain a multi-focal feature for thecorrection of presbyopia. Also, the anterior surface of the lens may betreated to reduce the variance in the pre-lens tear film.

In another embodiment of the present invention, the substantially rigidcontact lens portion is joined to an outer soft hydrophilic portion byan intermediate adhesion enhancement zone. The adhesion enhancement zonemay contain a material that bonds to the substantially rigid portion andto the soft hydrophilic portion. The soft hydrophilic portion may have aposterior surface that is spherical, aspherical, toroidal orrotationally asymmetrical to approximate the overall or meridionalsagittal depth of the peripheral cornea, limbal region and sclera. Theanterior surface of the soft portion may be modified to produce athickness variation in the form of prism ballast or thin zones thatutilize lid interaction to produce a resultant rotational stability.

The soft section or skirt of the contact lens is designed to controlrotation by various methods. The methods include prism ballasting, thinzones, and rotationally asymmetrical contours that match the asymmetryof the cornea, limbus and sclera. In the preferred embodiment thesuperior portion of the lens is thinner than the inferior portion.

Methods of Manufacturing a Hybrid Contact Lens

Referring to FIGS. 1–5, one method of manufacturing a hybrid contactlens according to the present invention will now be described. Thismethod results in a fracture resistant product that is inexpensive tomanufacture.

Shown in FIG. 1, a rod 10 of rigid gas permeable material is cast havingthe desired characteristics. Upon the completion of the curing the rodis precision ground to produce a substantially uniform diameter. The rodis then machined by tool 15 into a primary blank 17 having an anteriordiameter 20 designed to conform to the collet of a computer numericallycontrolled lathe and a posterior diameter 25 designed to conform theoutermost diameter of the hydrophilic portion of the lens forpositioning in a tube, cup, or other containing device. The anteriordiameter 20 may range from 6 millimeters (mm) to 24 mm, and theposterior diameter 25 may range from 6 mm to 24 mm. In one embodiment,the anterior diameter 20 may be a separate material that is bonded orotherwise attached to the primary blank 17 for enduring the clampingforce of a lathe. The intermediate portion of the primary blank 17 issimultaneously machined to have a predetermined angle 30 for theinterface of the rigid and hydrophilic material in the finished lens.

One manufacturing method of the present invention has the posteriordiameter 25 substantially meet, or exceed, the hydrophilic sectionoutermost diameter 35, that is, the outermost diameter of the softsection of the contact lens, as shown in FIG. 4. In this embodiment, aboundary material 40 is then applied to produce a resultant wall, or cupto receive, and retain the hydrophilic liquid polymer. Alternatively,the primary blank 17 may be inserted into a cup, tube or othercontaining device to receive the hydrophilic material.

An alternative manufacturing method of the present invention includesthe application of an adhesion promoter to the primary blank 17,followed by the casting of the hydrophilic polymer into the liquidholding device formed by either the boundary material 40, tube, cup orother containing device.

In yet another embodiment, the primary lens blank 17 is mounted via theanterior diameter 20 in the collet of a computer numerically controlledlathe that is programmed to produce the aspherical posterior surfaceprofile in a manner that the profile does not require polishing, or mayonly need a light buff, or polish. The posterior surfaced button is thenmounted to a lens block wherein the axis of the block passes through thegeometric center of the lens 45, shown in FIG. 4.

The assembly with the posterior surfaced button is remounted in thecollet of a computer numerically controlled lathe, such as the Optoform80 with Variform attachment, or equivalent type that is capable ofproducing rotationally symmetrical or non-symmetrical surfaces to high,or quarter wavelength accuracy that preferably require a light buff, orno supplemental polishing (VARIFORM and OPTOFORM are trademarks ofPrecitech, Inc., of Keene, N.H.). It will be appreciated to thoseskilled in the art that other types of lathes may be employed. Thefinished lens is then removed from the lathe, with or without a lightbuff, deblocked and cleaned followed by anterior lens surface treatment.Finally the lens undergoes hydration-extraction, sterilization andpackaging.

Alternative manufacturing methods of the present invention may include:molding of the posterior surface and diamond turning of the moldedblank; contour cutting of the anterior surface of a posterior curvefinished blank; etching the anterior surface of a posterior curvefinished blank or predicate lens anterior or posterior surface; thinfilm deposition of a predicate lens anterior or posterior surface; andlaser ablation of a predicate lens anterior or posterior surface.

Another manufacturing method may include molding or lathing a standardbase curve with a standard or semi-customized front surface, then usinga thermal or laser energy to modify the refractive index of the centermaterial to a desired optical requirement. This method replaces customlathing or molding expenses. Another method may include molding theposterior and anterior surfaces, and yet another embodiment may includea mechanical force or thermal molding manufacturing method.

Another method of manufacturing a hybrid contact lens according to thepresent invention is illustrated in FIG. 5. Step 1 shows a rod offluorosiloxane acrylate RGP material that will comprise thesubstantially rigid section of the hybrid contact lens. It will beappreciated to those skilled in the art that other types of materialsmay be employed. These other materials may include the followingmonomers, monomer mixtures, or their derivatives: methyl methacrylate;ethyl methacrylate; ethylene glycol diacrylate; octafluoro pentylmethacrylate, tetramethyldisiloxane, ethylene glycol dimethacrylate,pentafluoro phenylacrylate, 2-(trimethylsiloxyl)ethyl methacrylate,2,2-bis(2-metharyloxyphenyl)propane,N-[2-(N,N-dimethylamino)ethyl]acrylate, 2-(N,N-dimethylamino)ethylmethacryalte, 2-(N,N-dimethylamino)propy acrylate,N-vinyl-2-pyrrolidone, N,N-dimthylacrylamide, acrylamide, acrylamine,2-hydroxyethyl methacrylate, siloxane-ethylene glycol dimethacrylate,trifluoroethyl methacrylate, pentafluorostyrene, pentafluorophenylmethacrylate, pentafluorophenyl acrylate, pentafluoropropylmethacrylate, unsaturated polyester; p-vinyl benzylhexafluoroisopropylether, and siloxanylalkylamide.

The rod, or button shown in Step 1 of FIG. 5, will preferably have a 5millimeter (mm) to 22 mm diameter and be 2 mm to 15 mm in length. In oneembodiment, the button may be bonded to another material for asubsequent operation, and as a possible cost saving. In Step 2, a plungetool is used to remove unnecessary hard material and allow a solidsection of material on one side for subsequent operations. Anothermethod may use the plunge tool to form the button assembly from Step 1,with a shape similar to FIG. 2.

In Step 3, a spacer is formed on the gripping side of the blank for thenext operation, or the blank can be bonded to a pre-form containingdevice to skip Step 4.

In Step 4, a tape, or other media that provides a retaining wall to holdthe soft material during polymerization is applied to the blank. In Step5, an adhesion promoter may be applied to the hard material and then thesoft material is poured inside the retaining wall, or other containingdevice, and allowed to cure. In Step 6, the spacer, or containingdevice, is removed and the blank is ready for subsequent manufacturingoperations.

Referring to FIG. 6, methods of coupling the hard section of the contactlens to the soft section will now be described. Conventional hybridcontact lenses are generally not durable, in part because of the weakchemical bonding between the hard and soft sections of the lens. Onefeature of the present invention is that a variety of couplingconfigurations are contemplated that securely couple the hard and softsections of a hybrid contact lens.

One embodiment of the present invention employs an angled, or slopedsurface between the hard and soft contact lens sections, therebyincreasing the surface area, and thus the bonding force, or strengthbetween the two sections. Other embodiments use a variety of differentsurface features, or surface geometries that increase the durability andcomfort of a hybrid contact lens.

For example, the bonding angle 50, shown in FIG. 6, may vary from almost0 degrees to almost 90 degrees. That is, if a contact lens constructedaccording to the present invention was pressed against a flat surface,the angle defined by the interface between the hard and soft sections ofthe lens could vary from almost parallel to the flat surface to almostperpendicular to the flat surface.

In addition, the interface between the hard and soft sections of thecontact lens may include a variety of surface configurations, orgeometries 55. As shown in FIG. 6, these surface geometries 55 mayinclude ledges, protuberances, or substantially V- or W-shapedprojections. Other surface geometries 55 may include serrations,gradations, or any other shape that is not substantially straight, orplanar.

Referring now to FIG. 6A, a preferred hard-soft lens bonding method isillustrated. In this embodiment of the present invention, increasing thesurface area between the rigid and soft lens components increasesbonding strength between the two materials and minimizes lens breakage,or failure. Another advantage of this embodiment is that it provides asmooth transition between the rigid or hard, and soft materials. Thisproduces an exceptionally comfortable lens.

As shown in FIG. 6A, an interface, or junction 75 between the hard, orsubstantially rigid lens material 65, and the soft lens material 70 isillustrated. Also shown is angle “A” that may range between about 95degrees to about 170 degrees. In a preferred embodiment, angle A rangesbetween about 110 degrees to about 165 degrees. As illustrated, theinterface between the hard, or substantially rigid lens material 65, andthe soft lens material 70 is substantially V-shaped. Put differently,the interface comprises two intersecting planes that meet within thelens. This lens junction configuration provides a safety feature in theunlikely case of lens material separation during wear. Because of theV-shape, the edge of the hard lens material 65 is not “blade” shaped,and thus a sharp edge will not contact the cornea or eyelid, eliminatingthe risk of cuts, or abrasions.

The hard and soft sections of a contact lens constructed according tothe present invention may be joined, or coupled by a bonding material orresin comprised of the following monomer mixtures or their derivatives:vinyl acetate; trifluoroethanol; methyl methacrylate; ethylene diamine;2-hydroxyethyl methacrylate (HEMA) and other esters of methacrylic acidformulated from acrylic bases with fluorinated alkyl or aryl, silicone,styrene moiety in the structure and resultant polymers such aspolystyrene; fluorine/styrene; and silicone/styrene.

The soft section of the contact lens constructed according to thepresent invention may be comprised of a variety of materials. Thesematerials may include the following monomer mixtures or theirderivatives: poly HEMA; hydroxyethyl acrylate; dihydroxypropylmethacrylate; polyethylaneglycol; acetoxysilane;(trimethylsiloxyethyl)methacrylate; trimethylesiloxy;ethyleneglycol-dimethacrylate; phenylethyl acrylate; and polyethyleneoxide. It will be appreciated to those skilled in the art that othertypes of materials may be employed.

Hybrid Contact Lens Surface Treatments

One feature of the present invention is that a variety of contact lenssurface treatments are contemplated. These surface treatments may beadded, for example, for the purpose of improving the comfort of the lensby means of improving the in-vivo wetting of the lens material. Anotherreason for using surface treatments is to create a uniform pre-lens tearfilm thickness. Variations in pre-lens tear film thickness induceaberrations while a uniform pre-lens tear film thickness allows theother aberration corrections to reach full effectiveness.

One embodiment of a hybrid contact lens constructed according to thepresent invention may include a surface treatment that provides uniformpre-lens tear film thickness between normal blinking action. Thesetreatments may comprise one or more of the following embodiments: 1)Plasma—the lens is placed in the presence of gases that are modified byoscillating electromagnetic energy. This creates a surface oxidationthat generate functional groups such as OH or NH on the lens surface,which make the lens surface more wettable; 2) Ionic surfactants—polarmolecules are presented to the ionic lens surfaces with a resultantbonding of the molecules to the surface. An example is sodium dodecylsulfide. The 12-carbon chain combined with lauryl sulfonic acid providesa substrate that supports a more uniform tear film thickness; 3)Non-ionic surfactants—The lens may be exposed to non-ionic surfactantsthat provide a film on the lens. An example is an ethylene glycol chain;4) Soluble polymers—films of soluble polymers can be applied to therigid gas permeable material after manufacturing. Examples are TEFLON,N,N-dimethyacrylamide and HEMA. Other types of surface treatments arealso contemplated.

Methods of Prescribing and Fitting a Hybrid Contact Lens

The present invention also contemplates methods of prescribing andfitting a hybrid contact lens. One method relates to non-rotating lensesfor correcting high order aberrations that include methods of placingthe coordinates of the aberration measurement over the coordinates ofthe pupil. Another comprises methods of placing a multifocal over thecoordinates of the pupil and customizing the design of the multifocalwith measurements of high order aberrations and pupil size.

One method of prescribing and fitting a hybrid contact lens employs aset of precision hybrid lenses with either spherical, aspherical ortoroidal posterior surfaces and spherical, aspherical or toroidalanterior surfaces. For a final monofocal lens, one embodiment contains aposterior aspherical surface and an anterior spherical surface. For afinal multifocal lens one embodiment contains a posterior asphericalsurface and an anterior aspherical surface.

One prescribing method of the present invention employs a centralregistration mark or marks concentric with the lens geometric centerthat are placed on either the anterior or posterior surfaces or withinthe matrix of either the rigid central portion, the intermediateadhesion enhancement zone or in the soft portion of a contact lens. Inthe preferred embodiment the rigid portion is at least 9 mm in diameterand a minimum of three marks are placed at a chord diameter of about 8mm. In the preferred embodiment the diameter of the overall lens isapproximately 14.0 mm.

A contact lens from the set with a posterior rigid surface thatapproximates the sagittal depth of the respective eye over the chorddiameter of the rigid portion is placed on the eye and allowed toequilibrate. The degree of rotational and translational movement isobserved. In the preferred embodiment the movement observed should beless than 5 degrees rotational and 0.3 mm translational. Upondetermination that the movement meets the required limit the residualhigh and low order aberrations are measured through the lens along withthe relative coordinates of the lens marks and the pupil margin, limbalmargin or other anatomical features. In the preferred embodiment aninstrument having the capability of detecting the lens marks and thepupil margin along with the residual high and low order aberrations isused.

An alternative embodiment of the present invention may includeinfrared-responsive marks, such as one or more registration marks, oneor more concentric marks, or other suitable marks, which emit or reflectinfrared light. For example, some types of wavefront aberrometers employinfrared light, which is generally in the form of a laser. Duringexamination of an eye fitted with a hybrid hard-soft contact lensconstructed according to the present invention, the infrared-reflectingmarks in the hybrid lens will be easily visible, enabling simultaneousevaluation of registration error, as well as aberrations. In oneembodiment, indocyan dye that fluoresces when exposed to ultravioletlight is employed, but it will be appreciated that other dyes, powders,or other types of ultraviolet and infrared-responsive products may beemployed.

Another method of prescribing and fitting a hybrid contact lens employsa set of precision rotating and non rotating hybrid contact lenseshaving known ocular surface profiles, optical corrections and thicknessprofiles. In one embodiment, the lenses contain circumferential marks inthe mid periphery. A lens is selected and applied to the eye and allowedto equilibrate. The coordinates of the marks and the pupil aredetermined. The aberrations of the lens-eye system are measured. Amathematical model provides analysis of the known thickness profile, theregistration error of the coordinates of the lens and the pupil, and theresidual lens-eye aberrations to derive the computer numericallycontrolled lathe files for diamond turning a resultant thickness profilefor a final contact lens having the same ocular surface profile.

For example, one prescribing and fitting method of the present inventionmay include the steps of: selecting the initial lens to conform to theshape of the underlying cornea; capturing an image of thecircumferential marks and the pupil margin; measuring the residual lowand high order aberrations of the lens-eye system; performing analysisutilizing the known ocular surface profile of the lens, the initial lensthickness profile, the registration error, and the residual lens-eyeaberration error to determine the resultant files for generating a finalcontact lens.

Another method of prescribing and fitting a hybrid contact lens employsa set of contact lenses having a known central zone ocular surfacegeometry, thickness, anterior surface geometry and diameter. Thepreferred residual lens eye aberration correction and coordinatedisparity are determined by clinical measurement, and the thicknessprofile variation is derived by computer modeling, or other methods, inorder to specify a superiorly performing lens.

Yet another method of prescribing and fitting a hybrid contact lensemploys a set of contact lenses with fixed ocular surface geometries,overall diameters and front surface geometries, over which clinicalmeasurements are made from which the final prescription parameters arederived by computation, or other methods.

Another method of the present invention comprises correcting visualacuity deficiencies in presbyopia by reduction of the residual lens-eyeaberrations. The method uses a set of hybrid contact lenses having aknown ocular surface profile and thickness profile and containingcircumferential marks for the purpose of registration of the finaloptical correction with the coordinates of the optical system of theeye. The method steps may include: selecting the initial lens to conformto the shape of the underlying cornea; capturing an image of thecircumferential marks and the pupil margin; measuring the size of thepupil in photopic, mesopic and/or scotopic illumination; measuring theresidual low and high order aberrations of the lens-eye system; andperforming analysis utilizing the known ocular surface profile, theinitial lens thickness profile, the registration error, the pupil sizeand the residual lens-eye aberration error to determine prescriptioninformation for generating a final contact lens. In one embodiment ofthis method, the diameter of the near focused optical correction may bein the range of about 1.8 mm to about 4.0 mm.

Another method of the present invention employs a multifocal contactlens and corrects visual acuity deficiencies in presbyopia by reductionof the residual lens-eye aberrations. The method uses a set ofmultifocal hybrid contact lenses having a known ocular surface profileand thickness profile and containing circumferential marks for thepurpose of registration of the final optical correction with thecoordinates of the optical system of the eye. The method steps mayinclude: selecting the initial lens to conform to the shape of theunderlying cornea having a multifocal anterior surface; capturing animage of the circumferential marks and the pupil margin; measuring thesize of the pupil in photopic, mesopic and/or scotopic illumination;measuring the residual low and high order aberrations of the lens-eyesystem; and performing analysis utilizing the known ocular surfaceprofile, the initial lens thickness profile, the registration error, thepupil size and the residual lens-eye aberration error to determineprescription information for generating a final multifocal contact lens.In one embodiment of this method, the diameter of the near focusedoptical correction may be in the range of about 1.8 mm to about 4.0 mm.

Another method of the present invention employs a multifocal contactlens and corrects visual acuity deficiencies in presbyopia by reductionof the residual lens-eye aberrations. This method also incorporatesinformation relating to a light transmittance pattern. The method uses aset of multifocal hybrid contact lenses having a known ocular surfaceprofile and thickness profile, light transmittance pattern, andcontaining circumferential marks for the purpose of registration of thefinal optical correction with the coordinates of the optical system ofthe eye. The method steps may include: selecting the initial lens toconform to the shape of the underlying cornea having a multifocalanterior surface; capturing an image of the circumferential marks andthe pupil margin; measuring the size of the pupil in photopic, mesopicand/or scotopic illumination; measuring the residual low and high orderaberrations of the lens-eye system; and performing analysis utilizingthe known ocular surface profile, the initial lens thickness profile,the registration error, the light transmittance pattern, the pupil sizeand the residual lens-eye aberration error to determine prescriptioninformation for generating a final multifocal contact lens. In oneembodiment of this method, the diameter of the near focused opticalcorrection may be in the range of about 1.8 mm to about 4.0 mm.

The above-described methods of prescribing and/or fitting a hybridcontact lens may also employ additional method steps or additionaldevices. For example: the method of determining the difference in thecoordinates of the center of the circumferential lens marks and thepupil margin may incorporate a reticle of a biomicroscope or a camerawith subsequent manual or electronic digital image detection. Inaddition, the method of measuring the residual aberrations of thelens-eye system may incorporate Shack-Hartmann aberrometry, aberrometersutilizing Tscherning technology, laser ray-tracing, holographic grid orTalbot interferometry technology.

Correction for Various Components of the Visible Light Spectrum

Aberrometry performed with the contact lens in place provides us withknowledge of the angles that the rays emerging from the anterior lensmake with respect to the visual axis. In the perfect case, the rayswould all emerge parallel to the visual axis. But as illustrated in FIG.7, in the presence of aberrations these rays make an angle with respectto the visual axis and this angle is not restricted to the plane of thepaper. To correct these aberrations, there are generally two variablesto modulate. The first variable is the slope of the contact lens at thepoint each ray emerges from the contact lens. Changing this slope willchange the direction of the ray exiting the eye via Snell's Law. Therewill exist a slope of the anterior or posterior contact lens surfacethat causes the ray to exit parallel to the visual axis. The secondvariable is the local lens thickness at the point where each ray exitsthe contact lens. As this thickness is adjusted, the slope of one orboth of the surfaces for the path of the ray at this point also needs tochange in order to keep the emerging ray parallel to the visual axis.There will exist a set of local thicknesses and slopes thatsimultaneously cause all of the emerging rays to be parallel to thevisual axis and keep the overall thickness of the lens reasonable, thatis, not too thin or too thick.

Aberrometry is normally only performed at one wavelength, usually in theinfrared. However, as illustrated in FIG. 8, the slopes of the variousrays will depend on the color of the light. In general, blue lights rayswill be more convergent than the green light rays. The red light rayswill be more divergent than the green light rays.

The dilemma now is which color rays should be made parallel to thevisual axis. If the eye responded equally to all colors in the visiblerange (wavelengths of about 380 nanometers (nm) to about 780 nm), youwould make the rays that corresponded to the middle wavelength parallelto the visual axis. In this manner, half of the light would be divergingand half of the light would be converging as it left the eye.

Referring to FIG. 9, for a uniform response, the center wavelength ofthe visible spectrum would be ideal for correcting aberrations since,the equal areas of the rectangles on either side of this wavelengthmeans equal amounts of energy is distributed around this wavelength.

However, the eye does not respond to all wavelengths the same. Thephotopic response curve, illustrated in FIG. 10, shows that the eye ismore sensitive to the red/green end of the spectrum. The same sort ofconcept as described above can now be used to determine the idealwavelength for correcting aberrations. The ideal wavelength gives equalareas under the photopic response curve on either side, as shown in FIG.10.

In addition to the variation in response of the eye to different colors,the present invention may also vary the transmission of the contact lensto different colors. This may be beneficial to reducing the effects ofchromatic aberration in the eye. If the contact lens transmission ismultiplied by the photopic response of the eye, a net response of theeye results, as illustrated in FIG. 11. One ideal wavelength is based onthis net response which again gives equal areas under the curve. Thisideal wavelength is then used as the target for correcting aberrationsby the means described above.

For example, for either a final monofocal or multifocal lens, oneembodiment hybrid contact lens constructed according to the presentinvention contains colorants that reduce the transmission at both theblue and red end of the visible spectrum thereby narrowing the band oftransmitted light and potentially shifting the peak of the transmissioncurve of the lens. A contact lens of the present invention may thereforeinclude color additives for the purpose of reducing light transmission,or color additives for the purpose of reducing chromatic aberration.

An alternative examples utilizes a calculation based on the knownbandwidth of a pre-existing lens material and the output of themonochromatic aberrometry measurement to determine the optimum lensthickness profile.

Methods of Manufacturing a Hybrid Contact Lens by Chemical Bonding

The present invention discloses a hybrid contact lens that providesclear vision, while featuring high gas permeability for enhancedcomfort. Methods of manufacturing such a hybrid contact lens aredescribed herein with respect to FIGS. 1–6. In accordance with theprinciples of the present invention, methods of manufacturing a hybridcontact lens by chemical bonding will now be described with respect toFIGS. 12–29. More particularly, the methods pertain to chemicallybonding a substantially flexible hydro-gel soft skirt portion to asubstantially rigid high DK gas permeable core center portion.

Suitable materials for the substantially flexible portion include, butare not limited to: hydroxyethylmethacrylate (HEMA); methyl methacrylate(MMA); Ethyl methacylate (EMA); aminoaklyl containing acrylate ormethacrylate; N-vinyl pyrrolidone (NVP); 2-methoxyethyl methacrylate(MEMA); ethylene glycol methacrylate (EGMA); trifluoropropylmethacrylate; pentafluoropentyl methacylate; N,N-dimethylacrylamide(DMA); acrylamide; methacylamide; tetramethyldisiloxane ethylene glycoldimethacrylate; perfluorophenyl methacrylate; 2-(trimethylsiloxyl)ethylmethacrylate; N-fluoroalkyl methacylamide;bis(2-methacryloxyphenyl)-propane;(N,N-dimethylamino-ethyl)methacrylate; and combinations of any of thesemonomers and/or silicone hydrogel formulations such Cibavisionlotrafilcon. As would be understood to those of ordinary skill in theart, the above list is by no means exhaustive as other soft skirtmaterials may be employed as the substantially flexible portion withoutdeparting from the scope of the present invention.

Suitable materials for the substantially rigid portion include, but arenot limited to: fluorosilicone acrylate; siliconated, styrene;fluoroacrylate; fluorometharylate, perfluorianted acrylate andmethacrylate; any high DK or Hyper DK gas permeable rigid contact lensbottoms with DK of 70 (ISO), such as Boston 7 Envision, Boston EO,Boston Equales, Boston Equalens 2, Boston XO, Fluoroperm 151, Fluoroperm92, Fluoroperm 92, Fluoro 700, Menicon SE-P, Menicon Z; any other highDK materials; and any combination of these materials. Of course, aswould be understood to those of ordinary skill in the art, this list isby no means exhaustive as other materials may be employed as thesubstantially rigid portion without departing from the scope of thepresent invention.

A method of manufacturing a hybrid contact lens using a molded cup willnow be described with respect to FIGS. 12–15. Referring to FIG. 12,molded cup 100 comprises horizontal surface 102, a cylindrical outerwall 104 disposed substantially normal to horizontal surface 102 and acylindrical inner wall 106. The area within inner wall 106 comprises acylindrical inner section 109 for receiving substantially rigidmaterial, and the area between the inner and outer walls comprises acylindrical outer section 111 for receiving substantially flexiblematerial.

Inner wall 106 preferably comprises a pre-form optical grade dividerthat divides the substantially rigid inner portion and the substantiallyflexible outer portion. In addition, inner wall 106 preferably isbondable with both rigid and flexible materials used to form the contactlens. Suitable materials for the molded cup include, but are not limitedto, polypropylene, polyethylene, polyethylene terephthalate (PET),polycarbonate and optical grade plastics. The inner and outer wallsoptionally are coated with an adhesive to promote bonding with theflexible and rigid portions.

Preferably, the molded cup remains part of the finished contact lens.Alternatively, portions of the molded cup may be removed during thecasting process. For example, inner wall 106 may be removed afterpouring and curing the substantially rigid portion, and outer wall 104may be removed after pouring and curing the substantially flexibleportion. According to some embodiments, molded cup 100 further comprisesa lower cylinder 108 that forms lower section 113, which is dimensionedto produce a gripping area that conforms to the collet of a computernumerically controlled lathe or other machining apparatus. In theseembodiments, horizontal surface 102 preferably includes a centralopening 110 such that lower section 113 may be filled duringmanufacturing. Alternatively, lower section 113 may be pre-filled beforemanufacturing. According to other embodiments, lower cylinder 108 is notprovided.

In the illustrated embodiment, inner wall 106 or divider 106 is disposedat an angle A with respect to horizontal surface 102. Angle A may be anyangle from about 5 degrees to about 175 degrees, but preferably isselected to maximize the bonding strength between the rigid and flexibleportions of the contact lens. Inner wall 106 optionally includes a bendB adapted to further increase the bonding strength between the rigid andflexible portions. As would be understood to those of ordinary skill inthe art, many alternative inner wall configurations may be employedwithout departing from the scope of the present invention. For example,examples of alternative bonding angles between the flexible and rigidportions are described above with respect to FIGS. 6 and 6A.Additionally, examples of alternative inner wall configurations will nowbe described.

Referring to FIG. 13A, molded cup 100 includes an alternative inner wall114 that is disposed substantially normal to horizontal surface 102(i.e., angle A is about 90 degrees). In addition, inner wall 114 doesnot include a bend. Referring to FIG. 13B, molded cup 100 includes analternative inner wall 116 that is disposed at an acute angle withrespect to horizontal surface 102. Referring to FIG. 13C, molded cup 100includes an alternative inner wall 118 that is disposed at an obtuseangle with respect to horizontal surface 102. Referring to FIG. 13D,molded cup 100 includes an alternative inner wall 120 including aplurality of bends B. Bends B preferably increase the bonding strengthbetween the rigid and flexible portions. Additionally, inner wall 120 isdisposed at an angle A with respect to horizontal surface 102. Similarto the embodiment disclosed above with respect to FIG. 12, angle A maybe any angle from about 5 degrees to about 175 degrees, but preferablyis selected to maximize the bonding strength between the rigid andflexible portions of the contact lens.

Referring to FIG. 14, a predetermined amount of liquefied resin ofsubstantially rigid material is poured within inner section 109 suchthat the material: (1) fills lower section 113 via opening 110, therebyforming gripping area 128; and (2) substantially fills inner section109, thereby forming substantially rigid portion 126. Then, the moldedcup is placed into a programmed curing environment and the rigidmaterial is cured with heat, UV light, or a combination of both.

Alternatively, a predetermined amount of liquefied resin ofsubstantially rigid material is poured within inner section 109 suchthat the material only fills lower section 113, thereby forming grippingarea 128. Then, the molded cup is placed into a programmed curingenvironment and the rigid material is cured with heat, UV light, or acombination of both. After curing, an additional predetermined amount ofliquefied resin of rigid material is poured within inner section 109such that the additional material substantially fills inner section 109,thereby forming substantially rigid portion 126. Then, the molded cup isagain placed into the programmed curing environment and the rigidmaterial is cured with heat, UV light, or a combination of both.

Referring to FIG. 15, after curing the substantially rigid material, apredetermined amount of liquefied resin of substantially flexiblematerial is poured into outer section 111, thereby forming substantiallyflexible portion 130. Then, the molded cup is again placed into theprogrammed curing environment and the flexible material is cured withheat, UV light, or a combination of both. After curing the flexiblematerial, the lens is ready to be lathed, or otherwise machined, into afinished, fracture-resistant hybrid contact lens.

A method of manufacturing a hybrid contact lens using a block mold willnow be described with respect to FIGS. 16–21. Referring to FIG. 16,block mold 134 comprises a pair of halves 136, 138 that are attachedalong a breaking plane 140. Block mold halves 136, 138 preferably aresymmetric about breaking plane 140. Block mold 134 further comprises acentral void 144, 146 that defines an upper section 144 and a lowersection 146. Central void 144, 146 forms an opening 150 in asubstantially horizontal top surface 152 of block mold 134 such that theupper and lower sections may be filled with liquefied resin of the rigidmaterial to form the hard portion of the contact lens.

According to some embodiments, lower section 146 preferably isdimensioned to produce a gripping area that conforms to the collet of acomputer numerically controlled lathe or other machining apparatus. Inthese embodiments, an opening 148 exists between the upper and lowersections such that lower section 146 may be filled with liquefied resinduring manufacturing. According to other embodiments, lower section 146is not provided.

Upper section 144 includes an outer wall 156 formed by an inside surfaceof the block mold halves. Outer wall 156 forms the shape of the junctionbetween the rigid and flexible portions of the contact lens. In theillustrated embodiment, outer wall 156 is disposed at an angle A withrespect to top surface 152. Angle A may be any angle from about 5degrees to about 175 degrees, but preferably is selected to maximize thebonding strength between the rigid and flexible portions of the contactlens. Outer wall 156 optionally includes a bend B adapted to furtherincrease the bonding strength between the rigid and flexible portions.As would be understood to those of ordinary skill in the art, manyalternative outer wall configurations may be employed without departingfrom the scope of the present invention. Some of these alternative outerwall configurations will now be described.

Referring to FIG. 17A, upper section 144 of the central void includes analternative outer wall 158 that is disposed substantially normal tohorizontal surface 152 (i.e., angle A is about 90 degrees). In addition,outer wall 158 does not include a bend. Referring to FIG. 17B, uppersection 144 includes an alternative outer wall 160 that is disposed atan acute angle with respect to horizontal surface 152. Referring to FIG.17C, upper section 144 includes an alternative outer wall 162 that isdisposed at an obtuse angle with respect to horizontal surface 152.Referring to FIG. 17D, upper section 144 includes an alternative innerwall 164 including a plurality of bends B. Bends B preferably increasethe bonding strength between the rigid and flexible portions of thecontact lens.

Referring to FIG. 18, a predetermined amount of liquefied resin ofsubstantially rigid material is poured into opening 150 such that thematerial: (1) fills the area within lower section 146, thereby forminggripping area 172; and (2) substantially fills upper section 144,thereby forming substantially rigid section 170. Then, the block mold isplaced into a programmed curing environment and the rigid material iscured with heat, UV light, or a combination of both. Alternatively, apredetermined amount of liquefied resin of substantially rigid materialis poured into opening 150 such that the material only fills the areawithin lower section 146, thereby forming gripping area 172. Then, theblock mold is placed into a programmed curing environment and thesubstantially rigid material is cured with heat, UV light, or acombination of both. After curing, an additional predetermined amount ofliquefied resin of rigid material is poured into opening 150 tosubstantially fill upper section 144, thereby forming substantiallyrigid section 170. Then, the block mold is again placed into theprogrammed curing environment and the rigid material is cured with heat,UV light, or a combination of both.

Referring to FIG. 19, after curing the substantially rigid material,block mold 134 is broken along breaking plane 140 and the cured sectionof rigid material (comprising rigid section 170 and gripping area 172)is removed from the block mold halves. At this point, the surface of thecured section of rigid material optionally is primed or coated forbetter bonding. Referring to FIG. 20, a guard 178, 180 comprising asubstantially horizontal section 178 and a cylindrical sidewall 180 isattached on top of gripping area 172 using a suitable adhesive.Referring to FIG. 21, a predetermined amount of liquefied resin offlexible material is then poured into the area between rigid section 170and sidewall 180, thereby forming substantially flexible portion 182.

With further reference to FIG. 21, the materials are then placed intothe programmed curing environment and the substantially flexiblematerial is cured with heat, UV light, or a combination of both. Thehybrid materials (i.e., rigid section 170 and flexible section 182) arenow primed to be lathed, or otherwise machined, into a finished,fracture-resistant hybrid contact lens. Unlike the embodiment disclosedwith respect to FIGS. 12–15, there is no wall or divider disposedbetween the rigid and flexible portions.

A method of manufacturing a hybrid contact lens using a base curve moldwill now be described with respect to FIGS. 22–24. Referring to FIG. 22,base curve mold assembly 190 comprises base curve mold 192, inner wall194 or divider 194, outer wall 196 disposed around the outercircumference of base curve mold 192. Optionally, one or more centeringwebs 198 are provided between the inner and outer walls to ensure properpositioning of inner wall 194 with respect to a vertically disposed baseplane 200 that passes through the center of base curve mold 192. Innerwall 194 acts as a separator and junction surface between the rigid andflexible materials. Inner wall 194 preferably is a pre-form opticalgrade divider that is bondable with both rigid and flexible materialsused to form the contact lens. According to some embodiments, inner wall194 is coated with an adhesive to promote bonding with the rigid andflexible portions.

In the illustrated embodiment, inner wall 194 is substantiallyvertically disposed (i.e., parallel to plane 200). However, similar tothe embodiments described above with respect to FIGS. 12–21, inner wall194 may be disposed at any angle from about 5 degrees to about 175degrees with respect to a horizontal plane. Through the process of trialand error an angle may be chosen that maximizes bonding strength betweenthe rigid and flexible portions of the contact lens. Inner wall 194optionally includes one or more bends B adapted to further increase thebonding strength. Of course, as would be understood to those of ordinaryskill in the art, many alternative inner wall configurations may beemployed without departing from the scope of the present invention.

Referring to FIG. 23, a predetermined amount of liquefied resin ofsubstantially rigid material is poured within inner wall 194 to fill thearea therebetween, thereby forming substantially rigid portion 202.Then, the base curve mold assembly is placed into a programmed curingenvironment and the rigid material is cured with heat, UV light, or acombination of both. Referring to FIG. 24, after curing the rigidmaterial, a predetermined amount of liquefied resin of substantiallyflexible material is poured into the area between inner wall 194 andouter wall 196, thereby forming substantially flexible portion 204.Then, the base curve mold assembly 190 is again placed into theprogrammed curing environment and the flexible material is cured withheat, UV light, or a combination of both. After curing the flexiblematerial, the outer wall and centering webs are removed and the anteriorsurface of the lens is ready to be lathed, or otherwise finished.

A method of manufacturing a hybrid contact lens using a base curve blockmold assembly will now be described with respect to FIGS. 25–29.Referring to FIG. 25, base curve block mold assembly 210 comprises basecurve mold 212 and a pair of block mold halves 214, 216 that aresymmetrically disposed about a vertical plane 218 passing through thecenter of base curve mold 212. Base curve block mold assembly 210further comprises a central void 222 disposed in the area above basecurve mold 212 between block mold halves 214, 216. Central void 222 isadapted to be filled with liquefied resin of the rigid material to formthe hard portion of the contact lens.

Central void 222 includes an outer wall 226 formed by an inside surfaceof the block mold halves. Outer wall 226 forms the shape of the junctionbetween the rigid and flexible portions of the contact lens. In theillustrated embodiment, outer wall 226 is disposed substantiallyparallel to vertical plane 218. However, similar to the embodimentsdescribed above with respect to FIGS. 12–24, outer wall 226 may bedisposed at any angle from about 5 degrees to about 175 degrees withrespect to a horizontal plane. Through the process of trial and error anangle may be chosen that maximizes bonding strength between the rigidand flexible portions of the contact lens. Additionally, outer wall 226optionally includes one or more bends B adapted to further increase thebonding strength. Of course, as would be understood to those of ordinaryskill in the art, many alternative outer wall configurations may beemployed without departing from the scope of the present invention.

Referring to FIG. 26, a predetermined amount of liquefied resin ofsubstantially rigid material is poured into central void 222 such thatthe material fills the area within central void 222, thereby formingsubstantially rigid section 230. Then, the block mold is placed into aprogrammed curing environment and the rigid material is cured with heat,UV light, or a combination of both. Referring to FIG. 27, after curingthe rigid material, block mold halves 214, 216 are separated and removedfrom base curve mold 212. Referring to FIG. 28, a curvilinear sidewall234 is attached around the perimeter of base curve mold 212 using asuitable adhesive.

Referring to FIG. 29, a predetermined amount of liquefied resin ofsubstantially flexible material is then poured into the area betweenrigid section 230 and sidewall 234, thereby forming substantiallyflexible portion 236. The materials are then placed into the programmedcuring environment and the flexible material is cured with heat, UVlight, or a combination of both. After curing the flexible material, thesidewall is removed and the anterior surface is lathed, or otherwisefinished.

A method of manufacturing a hybrid contact lens using a using apre-shape mold assembly including a pre-machined substantially rigidcenter portion as a molded insert of a soft-skirt mold will now bedescribed with respect to FIGS. 30–33. Referring to FIG. 30,substantially rigid center portion 250 is formed and cured before beingplaced in the mold assembly. According to some embodiments, the rigidcenter portion is pre-coated or pre-treated with an adhesive to promotebonding with the flexible outer portion. Referring to FIG. 31, pre-shapemold assembly 252 comprises a base curve mold 254 and a pair of blockmold halves 256, 258 that are symmetrically disposed about a verticalplane 260 passing through the center of base curve mold 254.

Pre-shape mold assembly 252 further comprises a substantiallybowl-shaped void 264 disposed between the base curve mold and the blockmold halves. Bowl-shaped void 270, 272 comprises an inner portion 270for receiving substantially rigid center portion 250 and an outerportion 272 that is filled with a substantially flexible material. Inaddition, pre-shape mold assembly 252 preferably includes a central void266 disposed in the area above base curve mold 254 between block moldhalves 256, 258. Central void 266 is dimensioned to permit thesubstantially rigid center portion to be inserted into inner portion 270after it is formed and cured. One or more injection apertures 274preferably are provided in the pre-shape mold assembly for filling theouter portion of bowl-shaped void 270, 272.

Referring to FIG. 32, a predetermined amount of liquefied resin ofsubstantially rigid material is injection into outer portion 270,thereby forming substantially flexible outer portion 276. Then,pre-shape mold assembly 252 is placed into a programmed curingenvironment and the flexible material is cured with heat, UV light, or acombination of both. Referring to FIG. 33, after curing the flexiblematerial, the mold is separated and the finished contact lens is removedfrom the mold. According to some embodiments, the contact lens mayrequire machining of the anterior or posterior surfaces before it isready for use.

As disclosed above with respect to FIG. 6, the bonding angle between theflexible and rigid portions of the contact lens may vary from almost 0degrees to almost 90 degrees. In addition, the interface between theflexible and rigid portions may include a variety of surfaceconfigurations, including, but not limited to, ledges, protuberances,substantially V- or W-shaped projections, serrations, gradations, andany other shape that is not substantially straight, or planar.Alternatively, as disclosed above with respect to FIG. 6A, a junctionmay be provided between flexible and rigid portions.

With further reference to FIGS. 30–33, the substantially rigid portionmay comprise one or more of the following monomers, monomer mixtures,and their derivatives: trimeththyl-siloxyl; methyl-methacrylate;ethyl-methacrylate; ethylene glycol di-methacrylate; octafluoropentyl-methacrylate; tetra-methyldisiloxane; ethylene glycoldi-methacrylate; pentafluoro phenylacrylate; 2-(trimethylsiloxyl)methacrylate; bis(2-metharyloxyphenyl) propane;N-[2-(N,N-dimethylamino)ethyl]; onethacrylate;N-[2-(n,n-dimethylamino)ethy]; methacryalte; vinyl-pyrolidone;N,N-dimathacrylamide; acrylamine; hydroxyethyl methacrylate; siloxaneethylene glycol di-methacrylate; trifluoroethyl methacrylate;pentafluorostyrene; pentafluoropropyl methacrylate; unsaturatedpolyester; p-vinyl benzyl hexafluoroisopropyl ether;siloxanylalkylamide; and combinations thereof. As would be understood tothose of ordinary skill in the art, many other materials may be used toform the substantially rigid portion without departing from the scope ofthe present invention.

For the embodiment disclosed with respect to FIGS. 30–33, thesubstantially flexible portion may comprise one or more of the followingmonomer mixtures and their derivatives: poly HEMA; hydroxyethylacrylate; dihydroxypropyl methacrylate; polyethylaneglycol;acetoxysilane; trimethylesiloxy; ethyleneglycol-dimethacrylate;phenylethyl acrylate; zero-gel; Silicon-Hydrogel; polyethylene oxide;and combinations thereof. As would be understood to those of ordinaryskill in the art, many other materials may be used to form thesubstantially flexible portion without departing from the scope of thepresent invention.

For the embodiment disclosed with respect to FIGS. 30–33, the pre-treator pre-coat between flexible and rigid portions of the contact lens maycomprise an adhesive or resin on or more of the following monomermixtures and their derivatives: vinylacetate; trifluoroethanol;methacrylate; ethanediamine; 2-hydroxyethylmethacrylate (HEMA) and otheresters of methacrylic acid formulated from acrylic bases; fluorine;silicone; fluorine/silicone; styrene and resultant polymers such aspolystyrene; fluorine/styrene; silicone/styrene; and combinationsthereof. As would be understood to those of ordinary skill in the art,many other materials may be used to form pre-treat or pre-coat withoutdeparting from the scope of the present invention.

Further methods of manufacturing a hybrid contact lens according to thepresent invention involve pouring the rigid and flexible materials inthe reverse order such that the flexible material is poured and curedbefore the rigid material. For the block mold embodiments, this willrequire the creation of blocks that fill the central void such that theouter, flexible portion may be poured and cured first. Additionalmethods involve pouring both rigid and flexible materials atsubstantially the same time, then curing the materials simultaneously.

Additional methods of manufacturing a hybrid contact lens according tothe present invention involve molding or lathing a standard base curvemold with a standard or semi-customized front surface, then using athermal or laser energy to modify the refractive index of the centermaterial to a desired optical requirement. Advantageously, these methodsreplace expensive custom lathing and molding operations. Further methodsinvolve molding both the posterior and anterior surfaces of the contactlens. Other methods involve the application of a mechanical force orthermal molding.

Alternative manufacturing methods of the present invention may include:molding of the posterior surface and diamond turning of the moldedblank; contour cutting of the anterior surface of a posterior curvefinished blank; etching the anterior or posterior surface of a posteriorcurve finished blank or predicate lens anterior or posterior surface;thin film deposition of a predicate lens anterior or posterior surface;and laser ablation of a predicate lens anterior or posterior surface.

Thus, it is seen that a hybrid hard-soft contact lens system, method,method of manufacture and article of manufacture is provided. Oneskilled in the art will appreciate that the present invention can bepracticed by other than the above-described embodiments, which arepresented in this description for purposes of illustration and not oflimitation. The description and examples set forth in this specificationand associated drawings only set forth preferred embodiment(s) of thepresent invention. The specification and drawings are not intended tolimit the exclusionary scope of this patent document. It is noted thatvarious equivalents for the particular embodiments discussed in thisdescription may practice the invention as well.

1. A method of manufacturing a hybrid contact lens, comprising the stepsof: providing a pre-shape mold having a convex surface and including aninverted bowl-shaped void, the inverted bowl-shaped void comprising acenter portion having a convex configuration and an outer portioncomprising a channel, the pre-shape mold comprising a base curve moldand a pair of block mold halves, the pre-shape mold defining at leastone aperture for filling the channel with a liquefied resin of flexiblematerial, the aperture disposed proximal to an end of the channel;inserting a pre-formed substantially rigid portion into the centerportion of the inverted bowl-shaped void; injecting a predeterminedamount of liquefied resin of flexible material into the channel throughthe at least one injection aperture such that the liquefied resin flowsupward along the convex surface from the end of the channel into contactwith a peripheral edge of the pre-formed substantially rigid portion;and curing the substantially flexible material.
 2. The method of claim1, wherein the pre-formed substantially rigid portion is pre-coated orpre-treated with an adhesive to promote bonding with the flexiblematerial.
 3. The method of claim 1, wherein the pair of block moldhalves are symmetrically disposed about a vertical plane passing throughthe center of the base curve mold.
 4. The method of claim 1, wherein thepre-shape mold includes a central void dimensioned to permit thesubstantially rigid portion to be inserted into the center portion ofthe inverted bowl-shaped void.
 5. The method of claim 1, wherein thematerials for the substantially rigid portion are chosen from the groupconsisting of trimeththyl-siloxyl; methyl-methacrylate;ethyl-methacrylate; ethylene glycol di-methacrylate; octafluoropentyl-methacrylate; tetra-methyldisiloxane; ethylene glycoldi-methacrylate; pentafluoro phenylacrylate;2-(trimethylsiloxyl)methacrylate; bis(2-metharyloxyphenyl-)propane;N-[2-(N,N-dimethylamino)ethyl]; onethacrylate;N-[2-(n,n-dimethylamino)ethy]; methacryalte; vinyl-pyrolidone;N,N-dimathacrylamide; acrylamine; hydroxyethyl methacrylate; siloxaneethylene glycol di-methacrylate; trifluoroethyl methacrylate;pentafluorostyrene; pentafluoropropyl methacrylate; unsaturatedpolyester; p-vinyl benzyl hexafluoroisopropyl ether;siloxanylalkylamide; and combinations thereof.
 6. The method of claim 1,wherein the materials for the substantially flexible portion are chosenfrom the group consisting of: poly HEMA; hydroxyethyl acrylate;dihydroxypropyl methacrylate; polyethylaneglycol; aectoxysilane;trimethylesiloxy; ethyleneglycol-dimethacrylate; phenylethyl acrylate;zero-gel; Silicon-Hydrogel; polyethylene oxide; and combinationsthereof.
 7. The method of claim 2, wherein the materials for theadhesive are chosen from the group consisting of: vinylacetate;trifluoroethanol; methacrylate; ethanediamine;2-hydroxyethylmethacrylate (HEMA) and other esters of methacrylic acidformulated from acrylic bases; fluorine; silicone; fluorine/silicone;styrene and resultant polymers such as polystyrene; fluorine/styrene;silicone/styrene; and combinations thereof.
 8. The method of claim 1,wherein the step of curing the substantially flexible material comprisesapplying heat, UV light, or a combination of both heat and UV light.